Skating on in-line roller skates is fast becoming one of the most popular outdoor activities. Recently, there has been an increase in competitive sport activities developed around the in-line roller skate, such as in-line speed skating and roller street hockey. These competitive sports have lead many in-line roller skate athletes to undertake more regimented workouts. Important to determining the quality of a workout is knowing the speed one is skating and the distance traveled, as well as information concerning one's cardiovascular system, e.g., heart-rate. In addition, many local municipalities have passed speed laws in various areas frequented by in-line roller skaters, thereby increasing the necessity of knowing the speed traveled during a workout.
There are many devices that can provide the aforementioned information to an athlete. U.S. Pat. No. 5,177,432 to Waterhouse et al. discloses a wireless velocity detector for a bicycle including a transmitter mounted onto the hub of a wheel and a receiver mounted onto the handlebars. The transmitter includes an LC oscillator producing a signal having a predefined frequency and a pair of mercury switches to ensure that the transmitter is energized only upon sensing rotary movement. A coil is connected to receive the signal from the LC oscillator and functions as the radiating element of the transmitter. The coil radiates a magnetic field in the plane of the wheel, once for each revolution of the transmitter. The speed of the rotating magnetic field is proportional to the rate of the wheel's rotation. The receiver includes a CPU, an LCD, driven by the CPU, and a set of coils. The set of coils detect the magnetic field generated by the transmitter to generate continuously changing analog signals. The analog signals are digitized by an analog to digital converter and then passed on to the CPU. The CPU processes the signals and displays the information represented by them on the LCD. For example, the signals may represent velocity, RPM of the wheel or distance traveled.
U.S. Pat. No. 4,780,864 to Houlihan discloses a wristwatch that also serves as a computer to display speed, distance and pedaling cadence. The wristwatch functions as a receiver and is and placed in a special mount attached to the handlebars of the bicycle. A first permanent magnet is attached to one of the wheels and a second permanent magnet is attached to the pedal sprocket. Sensors are disposed upon the frame of the bicycle and positioned to detect the magnets. The wristwatch is hard-wired to each sensor via the special mount. In this fashion, the sensors detect and transmit, to the wristwatch, the rate of revolution for both the wheel and the pedal sprocket. The wristwatch includes a CPU to process the data received from the sensors and produce the requisite information, such as speed and distance traveled.
U.S. Pat. No. 4,546,650 to Cameron discloses a speed and distance calculator for skis which includes a toothed wheel extending from the back of a ski to come into frictional contact with snow. Two magnets are attached to the toothed wheel inductively coupling the toothed wheel to a Hall effect device, which is mounted on the back of the ski. In this fashion, the toothed wheel functions as a transmitter and the Hall effect device functions as a receiver. The Hall effect device is hard-wired to a microprocessor. The microprocessor receives signals from the Hall effect device indicative of the rate of rotation of the tooth wheel and processes these signals to determine the distance traveled by the ski.
U.S. Pat. No. 4,454,411 to Hale et al. discloses a conventional odometer attached to the rear truck of a roller skate. The odometer includes a plurality of digit carrying discs, all interconnected by suitable shafts and gears, to produce a sequential display in a magnifying window indicating a distance travelled by the skate. A rubber wheel extending from the rear of the roller skate frictionally engages the ground. The rubber wheel is connected to a shaft of the odometer to transmit the number of revolutions the rubber wheel has undergone. The odometer is calibrated appropriately to properly indicate the distance travelled by the skate as a function of the revolutions of the rubber wheel.
A problem with the aforementioned prior art devices is that the transmitter and the receiver are designed to be communicated over a fixed radial distance, making them unsuitable for providing a real-time visual representation to a user of a roller skate.
Therefore, it is an object of the present invention to have a wireless speedometer providing a real-time visual representation of information, such as the speed and distance traveled, to a user of a roller skate.